1. Field of the Invention
The present invention generally relates to generating power from voltage gradients that exist naturally and in association with chemical changes across the interface of water saturated sediments and within stratified water bodies found in aquatic environments.
2. Related Art
Presently, low power (up to 1 Watt continuous average) consuming marine deployed unattended electronics (such as sonar beacons and sensors) are powered by batteries (including conventional lead-acid, alkaline, lithium and seawater), by solar cells, or by direct links to ground available power by means of power conducting cables.
Each of these conventional power sources suffer deficiencies. Conventional batteries are impractical sources of low power for more than one year because they are heavy, bulky, expensive, limited in duration by self-discharge (1-3 years), and commonly fail under deployment conditions in which they are contained in pressure-compensated or pressure resistant vessels. Seawater batteries specifically designed for low power consuming autonomous marine deployed instrumentation provide 1-2 Watts continuous power for up to three years, limited by depletion of the anode. Solar cells are impractical sources of long-term power for marine deployed instrumentation due to sensitivity to weather and difficulty in maintaining their integrity on the marine surface. Direct cables are impractical sources of low power for marine deployed instrumentation due to cost and logistics.
While it is known that microbial decomposition of organic matter in marine sediments and in stratified water columns will result in the utilization of a succession of oxidizing agents and that this creates a natural voltage gradient, such natural voltage gradients and associated processes are not known to have ever been used as a power source.
What is needed, and has not heretofore been provided, is a method and apparatus of providing power to aquatic deployed devices for prolonged time periods that takes advantages of the natural voltage gradients found at and below sediment-seawater interfaces or within euxinic water bodies.